----- Original Message -----
From: "Rodent of Unusual Size" <[EMAIL PROTECTED]>
To: "Brin-L" <[EMAIL PROTECTED]>
Sent: Wednesday, August 15, 2001 9:08 AM
Subject: Re: Black holes and such
> On 2001-08-15 at 09h04, possibly To Brin-L et al.,
> the keyboard of "Alberto Monteiro" chattered:
> >
> > A blackhole doesn't spin. Spin requires a physical
> > rigid body or some approximation to it, and a black
> > hole can only have mass, angular momentum and charge
>
> Uh? How can you have a non-zero angular momentum
> without spin? I believe that a spinless blackhole
> is a 'naked singularity,' neh? With an accretion cloud
> rather than a disc.
> --
Intrinsic angular momentum is typically called spin. However, that doesn't
mean something is spinning in the sense that a top spins. For example, if
one combines the upper limit for the size of an electron with the intrinsic
angular momentum of an electron, and imagines the electron as a small
sphere, one would calculate a surface that is traveling faster than the
speed of light (even if the sphere is a perfect hollow sphere). FWIW, that
was even true for the upper limit that was established 75 years ago.
Thinking about GR and QM stuff in classical terms can be useful in some
circumstances. In others, it just confuses one.
Dan M.
